AGas colic is a catch-all term that refers to abdominal pain in horses caused by excessive gas in any portion of the intestinal tract. In many instances, the diagnosis is made by exclusion of other specific conditions rather than actually identifying the location of the gas. If the horse’s flank regions are distended, the most likely location for the gas is in either the cecum or the large colon. In contrast, the adult horse’s flank region rarely distends if the gas is in the small intestine; this is not the case for foals, as excessive gas in the small intestine can cause marked distention of the foal’s abdomen.

Gas colic is an extremely common reason for horses to exhibit signs of abdominal pain and, fortunately, one that has a very good prognosis for survival. Although it is often extremely difficult to identify the inciting cause for the development of gas colic, inadequate access to roughage, poor parasite control, stress, and administration of certain anthelmintics have been implicated in certain cases.

Gas distention of the large colon is due either to excessive fermentation of feedstuffs or an inability of the horse to move gas along the tract. The latter could be due to alterations in normal intestinal peristalsis caused by inflammation of the intestinal wall or spasm of the intestinal muscles. In either case, as the intestine distends, pain-sensitive receptors in the intestinal wall are stimulated and signals are sent to the horse’s brain which cause the horse to experience abdominal pain. Horses respond to these signals by showing the signs that we associate with the presence of colic, most notably pawing, looking at the flank, stretching out, lying down, and, in some cases, rolling. It is when the horse begins to exhibit these signs that the horse’s owner and veterinarian become involved.

Complications from gas distention arise if the distended bowel becomes displaced or twists upon itself. Many horse owners are concerned that this may occur if the horse lies down or tries to roll. The likelihood that rolling causes intestinal displacements, however, is probably rather small. Instead, the fact that the gas distended portion of the intestine would naturally rise to the top of the abdominal cavity, suggests that twisting of the intestine occurs by itself. In other words, horses probably roll in response to the intestinal twist rather than cause the intestinal twist by rolling. For this reason, it seems reasonable to allow a horse to lie down as long as he does no harm to himself. If, however, the horse tries to roll violently and in the process increases the risk of hurting himself or his handlers, he should be forced to stand and walk